Improvement in safety devices for mainsprings



S. W. MORGAN. Safety Device for Main-Springs.

No. 212,042. Patented Feb. 4,1879.

WlTNESSES INVENTOR. .rflmfi/ MW A 2, mmw ,0] (iii? & M ATTORNEY! N.PETERS, PHOTO-LITHOGRAPHER, WASHNGTOH, D c.

UNITED STATES PATENT OEEIcE.

STEPHEN XV. MORGAN, OF XVINONA, MINNESOTA.

lMPROVEMENT IN SAFETY DEVICES FOR MAlNSPRlNGS.

Specification forming part of Letters Patent No. 212,04 dated February:1, 1879; application filed June 15, 1878.

To all whom it may concern:

Be it known that I, STEPHEN W. lhlORGAN, ot'lVinona, in the county of\Vinona and State of Minnesota, have invented a new and valuableimprovement in Preventers of Reaction oi'thehlainsprin gs of atches andI do hereby declare that the following is a full, clear, and exactdescription of the construction and opeation of the same, referencebeing had to the annexed drawings, making a part of this specification,and to the letters and figures of reference marked thereon.

Figure l is a plan view, showing present invention as in use in awatch-barrel. Fig. 2 is a sectional view on a horizontal line, showingthe mainspring in position inside the band or ring. Fig. is a detail,showing in horizontal section the band or rin Fig. 4 is a side elevationof the ring, showing the outwardlyproiccting spring arm of the band orring. Fig. 5 is a plan view, showing the band or ring made by fasteningthe end of the whirl on the outer band of the coil. Fig. 6 is a detailafter above manner of construction, and showing the spring unwound; Fig.7, another detail of same method of construction.

This invention relates to that class of devices or improvements inwatch-makin g which aredesignedforpreventing injury to the watchmechanism from the recoil ot' a broken main spring; and consists, moreparticularly, in a band or ring with its ends lapping, the inside endadapted to hook one end of the mainspring upon, and the outer end forengaging in a notch or on a projection on the inside of thegoing-barrel, and in a band or ring surrounding the mainspring, formedby fastening the end of the mainspring upon the outer coil, and havingintegral therewith an outwardly-extending spring arm or pawl to act as aratchet, whereby the ordinary use of the mainspring is preserved, andany injury from recoil in breaking is prevented, all as will now be morein detail set out and explained.

In the accompanying drawings, the letter A designates the going-barrelof a watch, havin g inside of its barrel a notch, a. 13 indicates a bandor drum formed of spring-steel by bending a piece of spring into theform of a ring, and passing a rivet through the lap, leaving aprojecting end, I), projecting outwardly. The other end, 'i, of thestrip is shaped, as shown in Fig. 4, to form a hook, i, for a pun posehereinafter set forth. This ring fits snugly in the spring-barrel, andthe outwardly-projecting end of spring-arm 71 engages the notch aaforesaid therein. 0 represents a mainsprin g having an eye, 0, at eachend, and of the usual form. The eye at the outer end of the spring ispassed over the hook i of the inwardly-projecting end of the band ordrum, and the spring is then coiled within it, the eye at the inner endof the said spring be ing engaged with the key-post, in the usualmanner. The outwardly-projecting arm I), being engaged with the notch aof the barrel, prevents the drum from moving forward during the windingof the spring; but should the spring break, the drum or band not only receives the force of the spread thereof, but its outwardly-projecting armZ), acting as a pawl or ratchet, escapes from the ratchet-notch a, andallows the said drum to revolve in the barrel independently of the same.

By this means the watch-movement is but little affected by the breakingof the spring, and the barrel sustains no injury whatever. Instead ofmerelyhookin g the end of the spring to the inwardly-projecting arm orend i of the band or drum, it may be riveted thereto, if i deem it mostexpedient.

It may sometimes be desirable to form the Outer whirl of the mainsprin ginto abandor ring by riveting its end to the body of the coil or whirlin the outer band, as is 110w shown in Fig. 5. In this instance theoutwardly-ex tending spring arm or pawl may be struck out of the metal,or made as before stated.

In adapting my present invention to sprin now in use, the form now shownin Fig. 3 may be employed to best advantage; but in new watches it maybe preferred to adopt the form now illustrated in Fig. 5.

I am aware that heretofore a spring has been fixed in the side of a casefor hcldin g the mainspring; but this method of construct on isexpensive, and liable to injury from dirt, and not easy to clean; also,that a spring or pawl arm has been cut out of the end of the mainspringitself; but this construction will not allow the mainspring to bereadily han-' dled in the trade and by the watch-maker, since the springis not confined, nor will the mainspring insure an even and regularpressure of the pawl-arm against the sides of the going-barrel, andhence will not always be sure to act. Therefore I do not 110w lay anyclaim to either of these devices or to the inventions indicated in them.

What I claim as new, and desire to secure by Letters Patent, isv 1. Aring or band for containing the mainspring of a watch, fastened togethernear its ends, the inner end adapted to attach an end of the mainspringupon, and the other constituting a spring arm or pawl adapted to en- O.B. GOULD, O. G. MAYBURY.

